A New Orleans police officer was shot and killed early Friday, ambushed while getting out of a patrol car to investigate something which had aroused suspicions on the city’s east side, police said.

The accused shooter, a man believed to be 30 years old, was also shot when officers returned fire, Police Superintendent Michael Harrison told reporters at an early morning news conference.

At least one — possibly two — officers returned fire “and our officer collapsed right there on the scene,” Harrison said.

“They were on routine patrol,” he said. “They saw something that aroused their suspicion. They were exiting the vehicle and upon exiting the vehicle what we have learned is that this perpetrator fired at our officer, striking our officer.”

The suspect fled inside an apartment, which was then surrounded by a SWAT team, Harrison said. The police department’s negotiation team was also called to the apartment and negotiations with the accused gunman eventually led to a peaceful surrender, he said.

“We have lost one of our brothers. NOPD grieves this morning,” the New Orleans Police Department said in a pre-dawn tweet.

“We are all grieving,” Harrison told reporters. “Our department is grieving, our city is grieving and this family is grieving so we ask the city to pray for us and keep us in our thoughts and prayers.”

The accused gunman was taken to a hospital with several gunshot wounds, Harrison said.

“There are a lot of officers that knew this officer really, really well and the entire department when this happens is in trauma and of course it strikes at the heart of the city,” New Orleans Mayor Mitch Landrieu told reporters.

“We talk to these officers at their graduation and of course we say this all the time about how dangerous this job really is and unfortunately tonight our worst nightmares have come to be,” Landrieu said.

At this stage in the investigation, police believe there was only one gunman involved, Harrison said. Police didn’t immediately identify the officer or the suspected gunman.